Inflicted abdominal and thoracic injury — formative SAQs

SAQ 1 (10 marks)

A 14-month-old presents with two days of vomiting, abdominal distension and fever. The carer attributes it to a 'tummy bug'. On examination the abdomen is rigid and guarded. You note a faint bruise over the flank. [1]

1. What injury patterns carry the highest specificity for inflicted abdominal injury, and why? (3) [1] [4]
2. Explain why a 'soft' early abdomen does not exclude a serious hollow-viscus injury. (2) [4]
3. Outline the laboratory occult-injury screen you would request and the imaging strategy for a stable child. (3) [3] [9]
4. State the safeguarding steps that must run concurrently with surgical management. (2) [1]

Model answer

1. Duodenal and jejunal injury, pancreatic injury, and mesenteric injury carry the highest specificity because they require substantial, directed force on retroperitoneal or mobile viscera that a short fall cannot generate; a hollow-viscus perforation in a pre-verbal child is abuse until proven otherwise. [1] [4] [8]
2. Full-thickness duodenal or jejunal perforation leaks enteric contents and peritonitis with sepsis builds over 24–48 hours, so the abdomen may be soft initially and a rigid abdomen is a late sign; delayed presentation is itself a marker of abuse. [4]
3. Draw AST and ALT (liver), lipase and amylase (pancreas), troponin if chest injury, FBC, lactate, coagulation and group-and-save; for a stable child, request contrast-enhanced CT of the abdomen and chest and a high-detail skeletal survey with oblique rib views, repeated at two weeks in any child under two. [3] [7] [9]
4. Notify the child-protection team during resuscitation, file the mandatory report required by jurisdiction, document and photograph injuries, and convene a multi-disciplinary case conference; never discharge to the index household before the assessment is complete. [1]

SAQ 2 (10 marks)

A 3-month-old infant is admitted with respiratory distress. Chest radiograph shows multiple posterior rib fractures. The carer reports a 'minor fall' and 'some CPR'. [5]

1. What is the significance of posterior rib fractures in an infant? (3) [5] [7]
2. Critically evaluate the claim that rib fractures were caused by cardiopulmonary resuscitation. (3) [6]
3. Justify the imaging strategy for this infant, including the skeletal survey and any cardiac screening. (2) [7] [9]
4. What is the disposition, and what follow-up is required? (2) [1]

Model answer

1. Posterior rib fractures are caused by an adult squeeze that levers the rib head against the transverse process; their positive predictive value for non-accidental trauma in an infant is around 95 per cent, and multiple fractures of different ages strengthen the inference further. [5] [7]
2. Maguire's systematic review shows rib fractures from CPR are rare and usually anterior or lateral when they occur; posterior and multiple lateral-arc fractures are not explained by CPR, so the claim does not exonerate abuse and a full work-up is required. [6]
3. Request a high-detail skeletal survey with oblique rib views and a repeat at two weeks to reveal callus, plus chest imaging for pulmonary contusion, pneumothorax or haemothorax; measure serum troponin to screen for cardiac contusion. [7] [9]
4. Admit for observation, occult-injury screening and child-protection assessment; do not discharge to the index household before the MDT case conference agrees a safe destination; arrange follow-up imaging for rib healing and any pancreatic or solid-organ surveillance. [1] [7]